A repeater system (such as a distributed antenna system (DAS), a single-node repeater, a radio frequency (RF) repeater, etc.) is typically used to improve the wireless radio frequency (RF) coverage provided by one or more base stations. A repeater typically picks up and sends radio signals to a base station via antenna with a directional radio pattern. A repeater system typically includes one or more master units that are communicatively coupled with a plurality of remote antenna units, where each remote antenna unit can be coupled directly to one or more of the master units or indirectly via one or more other remote antenna units and/or via one or more intermediary or expansion units. A repeater is typically used to improve the coverage provided by one or more base stations that are coupled to the master units. These base stations can be coupled to the master units via one or more cables or via a wireless connection, for example, using one or more donor antennas. The wireless service provided by the base stations can include commercial cellular service and/or private or public safety wireless communications.
The use of repeaters provides added capacity as well as additional coverage. Safety-related RF systems are typically activated on demand or are operated continuously. The safety wireless capacity provided by a repeater and the associated base-station-related equipment during normal operations may not be sufficient in emergency situations (such as a fire or security event) due to the presence of many additional users of the safety wireless service. As a result, it is common to provision systems used for such safety applications with additional base stations and repeaters. In safety-related systems a redundant configuration must be activated in a short amount of time otherwise dropped calls may occur.
When planning for coverage within public safety relevant facilities by emergency services providers, the signal distributing infrastructure of the system may be shared between private and public safety services, each operating on their own frequency bands. For example, the assigned licensed bands for the German Public Safety Digital Radio (BDBOS) TETRA network in Germany are 380-385 MHz for uplink communications and 390-395 MHz in downlink communications. For private safety services, different bands are used. For example, 415-420 MHz may be used for uplink communications and 425-430 MHz may be used for downlink communications for private safety services. Public safety signals are usually used by government agencies, such as police or fire, and public safety coverage is available from base stations provided across large geographic regions (for example, nationwide coverage). Private safety signal coverage, in contrast, is usually found within specific facilities or other areas of private service responsibility, for example, for the use of facility operator.
A repeater system may be implemented as an “active” system in the sense that the downlink and uplink RF signals are amplified before being repeated. Active repeater systems can be used, for example, in sport stadiums, buildings (hotels, malls, or trade centers), metro stations and airports, trains, and tunnels. Each base station can be coupled to the repeater system via one or more cables or via a wireless connection, for example, using one or more donor antennas. Repeater systems can be used in other applications.
The capacity of each base station coupled to a repeater system may be dedicated to the repeater system. The capacity of each base station coupled to a repeater system can also be shared among the repeater system and a base station antenna system that is co-located with the base station and/or shared among the repeater system and one or more other repeater systems.
As discussed above, repeaters provide wireless communication coverage in buildings for commercial use and for public services, like rescue services. The repeater usually picks up the radio signal from a base station signal by an antenna with a directional radio pattern towards a specific base station. For public services, the coverage needs to be provided also in emergency situations or more generally under abnormal conditions, like fires or maintenance of the base station. A normal condition is defined for example, when the primary base station is on-duty and the primary signal line connecting the antenna with the repeater is undisturbed. An abnormal condition is defined for example, when the primary base station is off-duty due to maintenance, or the primary signal line is broken. Other abnormal condition examples may include a primary in-building signal path being broken, signal loss due to increase free space loss by obstacle and an antenna failure/damage/misalignment. Other abnormal conditions are possible.